A technology for networking a plurality of electronic devices, such as a plurality of servers or a plurality of processing units, that communicate with each other. Examples of such a technology include a technology for connecting the electronic devices by a plurality of networks to increase the bandwidth used by the electronic devices for communication, or to secure redundancy for improving the reliability of communication.
Hereinafter, a description is given of an example of the technology for connecting a plurality of electronic devices by a plurality of networks with reference to FIG. 23. FIG. 23 is a diagram illustrating an example of servers connected to a plurality of networks. In the examples illustrated in FIG. 23, servers a to d are simply described as a to d.
For example, in the example illustrated in (y) of FIG. 23, the servers a to d are connected to a network including switches 20 and 20a to 20c. In detail, the servers a and b are connected to the switch 20b, and the servers c and d to the switch 20c. Moreover, each of the switches 20b and 20c is connected to the switches 20 and 20a. 
On the other hand, in the example illustrated in (z) of FIG. 23, the servers a to d are connected to the network including the switches 20 and 20a to 20c, and a network including switches 20d to 20g. In detail, as in the example illustrated in (y) of FIG. 23, the servers a to d are connected to the network including the switches 20 and 20a to 20c. Moreover, the servers a to d are connected to the network formed by the switches 20d to 20g, the network having the same topology as the network including the switches 20 and 20a to 20c. 
As a consequence, in the example illustrated in (z) of FIG. 23, the servers a to d communicate via the network including the switches 20 and 20a to 20c, or the network including the switches 20d to 20g. As a consequence, in the network illustrated in (z) of FIG. 23, the bandwidth between the servers a to d is increased to the double of the network illustrated in (y) of FIG. 23.
Patent Document 1: Japanese Laid-open Patent Publication No. 2000-253060
However, if a plurality of electronic devices is connected to a plurality of networks having the same topology, there is a problem that it is not possible to reduce latency upon communications between the electronic devices.
For example, in the example illustrated in (y) of FIG. 23, the servers a and c perform communication on a communication channel via three switches 20b, 20, and 20c, or switches 20b, 20a, and 20c, in other words, a communication channel with the hop count of “three”. As illustrated in (z) of FIG. 23, the network including the switches 20d to 20g has the same topology as the network including the switches 20 and 20a to 20c. Hence, if the servers a and c are communicated via the network including the switches 20d to 20g, communication is performed on the communication channel with the hop count of “three” as in the case where communication is performed via the network including the switches 20 and 20a to 20c. 
In this manner, if the servers a to d are connected to the plurality of networks having the same topology, it is not possible to reduce latency in the communication between the servers a to d although the plurality of networks is connected to the servers a to d.